Parallel and comparative analysis of the proteome and transcriptome of sorbic acid-stressed Saccharomyces cerevisiae

Exposure of Saccharomyces cerevisiae to 0.9 mM sorbic acid at pH 4.5 result ed in the upregulation of 10 proteins; Hsp42, Atp2, Hsp26. Ssa1 or Ssa2, Ss b1 or Ssb2, Ssc1, Ssa4, Ach1, Zwf1 and Tdh1; and the downregulation of thre e proteins; Ade16, Adh3 and Eno2. In parallel, of 6144 ORFs. 94 (1.53%) sho wed greater than a 1.4-fold increase in transcript level after exposure to sorbic acid and five of these were increased greater than two-fold; MFA1, A GA2, HSP26, SIP18 and YDR533C. Similarly, of 6144 ORFs, 72 (1.17%) showed g reater than a 1.4-fold decrease in transcript level and only one of these, PCK1, was decreased greater than two-fold. Functional categories of genes t hat were induced by sorbic acid stress included cell stress (particularly o xidative stress), transposon function, mating response and energy generatio n. We found that proteomic analysis yielded distinct information from trans cript analysis. Only the upregulation of Hsp26 was detected by both methods . Subsequently, we demonstrated that a deletion mutant of Hsp26 was sensiti ve to sorbic acid. Thus, the induction of Hsp26, which occurs during adapta tion to sorbic acid, confers resistance to the inhibitory effects of this c ompound. Copyright (C) 2001 John Wiley & Sons, Ltd.